506th may refer to:
506th Air Expeditionary Group, provisional United States Air Force unit 506th Air Refueling Squadron, inactive United States Air Force unit 506th Airborne Infantry Regiment Association, charitable veterans' organization 506th Bombardment Squadron, inactive United States Air Force unit 506th Fighter Squadron, unit of the Oklahoma Air National Guard that flies the KC-135 Stratotanker 506th Infantry Regiment (United States), an airborne forces regiment of the US Army
See also 506 (number) 506, the year 506 (DVI) of the Julian calendar 506 BC E Company, 506th Infantry Regiment (United States), one of the best-known companies in the United States Army